Assessing material problems and lifetime of primary circuit components for Czechoslovak nuclear power plants

The major R+D projects of the Nuclear Research Institute (UJV) dealing with reactor materials for Czechoslovak nuclear power plants are discussed. These include, first of all, examination of the temperature dependence of impact toughness of 15Kh2NMFA steels for WWER-1000 pressure vessels. Hot and semihot laboratories were also built up, making possible the implementation of a complex approach to the programme of surveillance of samples of pressure vessels at all Czechoslovak nuclear power plants. UJV is the only institution in Czechoslovakia having available irradiation facilities for assessing the radiation resistance of reactor materials, viz., the WWR-S research reactor and CHOUTA irradiation probes. An expert system has also been developed, enabling damage of fuel element cladding to be predicted and the state of the cladding to be checked in in-service conditions. This system is being tested at the Dukovany nuclear power plant. (Z.M.). 9 figs., 10 refs